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Drones that enable the improved monitoring of agricultural practices

In partnership with the start-up company AIRINOV, INRA scientists in Avignon are involved in a pilot operation on the use of drones to ensure the satisfactory agronomic management of arable crops and vineyards.

drones for better monitoring of agronomic practices. © INRA, F. Barret
Updated on 02/14/2018
Published on 11/12/2013

Drones equipped with on-board GPS

The device developed by AIRINOV enables the rapid overflight of plots at an altitude of between 20 and 150 metres, the drone's actual position being known thanks to its on-board GPS.  A camera fixed under the drone is able to record images continuously during flight in four spectral bands.  In parallel, a sensor installed on the ground measures the level of incident radiation, thus enabling calculation of the spectral reflectance used to identify different crop characteristics.

 

A radiative transfer model

The images are exploited using a physical radiative transfer model that can simulate the signal recorded by the sensor, based on the description of the cover structure and the optical properties of its elements and the ground.  This model is "reversed" to estimate certain crop characteristics (leaf surface area, chlorophyll content) using measurements by the drone at each image point.  These characteristics are then used as indicators for decision-making rules, particularly to optimise nitrate fertilisation.  Multiplying the number of images taken of part of a plot seen from different angles during passage of the drone also enables a 3D reconstruction of the cover, which is particularly useful when characterising crops grown in rows, such as vines.

 

Experiments under way on wheat, rapeseed and vines

Plots cultivated with wheat and rapeseed are being used for trials in Auzeville (43.53°N, 1.50°E) and Mauprévoir-Durantière (46.16°N, 0.53°F), respectively.  These crops are overflown at different phenological stages.  In parallel, reference measurements of leaf surface area and chlorophyll content are being made to evaluate the accuracy of the method.  The initial results are very promising with respect to wheat and rapeseed, with an accuracy of about 15% for leaf surface area, and very good repeatability.  Other trials are also under way on vineyard plots.

 

Drones: promising tools for agriculture

Drones enable the collection of key data on cultivated plots and have proved their efficiency in characterising the vegetation on wheat and rapeseed crops.  Their use on barley, maize or vines is currently being tested.  These remote sensing tools have become valuable allies for farmers who wish to optimise management of their nitrogen inputs.

For further information

  • F. BARET and A. VERGER, “Report on the development of an algorithm for estimating GAI from UAV images over wheat and rapeseed crops”, INRA UMR114 EMMAH, UMT CAPTE, Avignon, 26/07/2013, 11 pages.
  • F. BARET, B. DE SOLAN, R. LOPEZ-LOZANO, K. MA, M. WEISS (2010). GAI estimates of row crops from downward looking digital photos taken perpendicular to rows at 57.5° zenith angle. Theorical considerations based on 3D architecture models and application to wheat crops. Agricultural and Forest Meteorology, 150, 1393-1401.